Document Details

Document Type : Article In Journal 
Document Title :
Reaction Mechanism and Deactivation Modes of Heterogeneous Catalytic Systems
أساليب الإبطال لأنظمة محفّزة مختلفة و آليّة التّفاعل
 
Subject : Reaction Mechanism and Deactivation Modes of Heterogeneous Catalytic Systems 
Document Language : English 
Abstract : Solving the problem of catalyst deactivation is essential in process design. To do this, various aspects of the kinetics of processes with catalyst deactivation, and their different mechanisms, are discussed. Catalyst deactivation often cannot be avoided, but more knowledge on its mechanism can help to find kinetic means to reduce its harmful consequences. When deactivation is caused by coke, the generation of coke precursors is the determining step in the deactivation kinetics. Different types of deactivation were distinguished that lead to different evolution of the process. The phenomenon of non-uniform coking can be linked to catalyst surface non-uniformity. For the class of catalysts with more than one type of active sites, an explanation was suggested for the observed trends in the deactivation modes. For catalytic processes using catalyst particles of industrial size, the influence of intraparticle diffusion resistance is important. The analysis showed that for a number of processes, the decrease of the reaction rate due to deactivation is less under diffusion control. For certain reaction mechanisms, there exist operation conditions where the rate of the process under diffusion control exceeds the rate in the kinetic control regime. A significant problem is the change of selectivity in the course of catalyst deactivation. The selectivity may either decrease or increase, and depends on the reaction mechanism during deactivation. The changes are larger when there is no diffusion resistance. The intentional poisoning of catalysts and its influence on catalyst activity and selectivity for the process of ethylene oxide production was discussed. 
ISSN : 1319-0989 
Journal Name : Arts and Humanities Journal 
Volume : 53 
Issue Number : 6 
Publishing Year : 1428 AH
2008 AD 
Article Type : Article 
Added Date : Wednesday, February 9, 2011 

Researchers

Researcher Name (Arabic)Researcher Name (English)Researcher TypeDr GradeEmail
عبدالرحيم الزهرانيalzhrani, abdulraheem ResearcherDoctorate 
يحي الحامدAlhamed, yahia ResearcherDoctorate 
لاشيزار بتروفpatrov, lashzar ResearcherDoctorate 

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